[skinnymuch]

I’m almost certain the check is against what the number is behind. Also the opposite situation - Google Voice to carrier would result in issues if carrier to GV was fine. Not the case however.

The number needs to be non-VoIP. Off the top of my head, Uber, Lyft, Craigslist all require non-voip which means no Google Voice.

[_-___________-_]

They have databases that they look up, but they're notoriously inaccurate. If you can use a number from another country (not always possible since some services require an in-country number, but a surprising number don't) you'll often find it works better, especially if you choose a country where the database provider might have less access to information about which ranges are assigned to which providers.